ABSTRACT
EPIDEMIOLOGY Non-melanoma skin cancer (NMSC) is the most common malignancy worldwide. It is of particular relevance to the head and neck surgeon as sun-exposed regions of the head and neck are the most frequently involved sites for the development of NMSC (70-80% of cases). The vast majority of NMSC is basal cell carcinoma (BCC), which comprises 75% of cases, while cutaneous squamous cell carcinoma (cSCC) accounts for 20% of NMSC. A wide variety of additional non-melanoma skin tumors arise from other cell types present in skin, such as lymphocytes, vascular endothelial cells, Merkel cells, mesenchymal stromal cells, and cells forming the adnexal structures. These entities are quite rare relative to BCC and cSCC and will not be discussed in this chapter. Although the mortality from NMSC is relatively low, the morbidity and cost associated with treatment is substantial (1). Furthermore, the incidence of NMSC has increased markedly since the 1960s and continues to rise (2). This is generally believed to be a consequence of increased cumulative ultraviolet exposure and is related to an increasingly elderly population, change in outdoor activities, and depletion of the atmospheric ozone layer (3).
